Did you know that your digestive system contains your body’s ‘second brain?’

This second brain in the gut is the reason you get butterflies in your stomach when you’re nervous. Interestingly, your gut controls your digestive functions through the same nerve cells and chemical messengers that your brain uses.

Keep reading to learn more about the gut-brain connection and how it impacts your health.

What Is the Brain in the Gut?

The brain in the gut is known as the enteric nervous system (ENS). It’s part of the autonomic nervous system and consists of more than 100 million nerve cells that line the gastrointestinal tract. The ENS runs from the upper esophagus to the internal anal sphincter.

The ENS controls digestion through sensory and motor nerve cells. It normally communicates with the brain but can also function independently of the central nervous system (CNS). This is why it gets the name ‘second brain.’

The ENS stimulates bowel motility and gastrointestinal blood flow. It also regulates digestive enzymes, hormones, and nutrient absorption.

Understanding the Gut-Brain Connection

The gut-brain connection is a complex pathway of communication that involves the gut microbiome, ENS, vagus nerve, and immune system.

These connections send information about the gut to the CNS. But the CNS also relays information to the digestive system. For example, the sight and smell of appetizing food stimulate the stomach to secrete acid.

The vagus nerve, the 10th cranial nerve, provides the fastest connection between the gut and brain. It sends signals to the brain through sensory input from the gut, such as intestinal stretch, hormones, and neurotransmitters. For instance, a stretched intestine tells your brain that you have received enough nutrients and can stop eating.

The immune system also influences the gut-brain connection because the greatest concentration of immune cells resides in your gastrointestinal tract. Immune cells constantly communicate with the brain and update your health status. Inflammation in the gut and increased intestinal permeability can increase the risk of brain disorders. Similarly, changes in the brain can contribute to the development of digestive conditions.

gut-brain connection

How Is the Gut Microbiome Related to Mental Health?

Your gut health is closely related to your mental health. And your gut microbiome plays an important role.

The majority of microorganisms in the human body live in the gut. This is your gut microbiome. The gut microbiome contains a diverse community of yeast, archaea, parasites, and bacteria.

The bacteria in the gut control a variety of bodily functions, including:

  • Digestion
  • Metabolism
  • Brain function
  • Immune response
  • Vitamin synthesis

Your gut maintains a balance of beneficial and harmful microorganisms to keep your body healthy and functioning properly. But if your gut microbiome becomes imbalanced, it can negatively affect the gut and brain. A gut microbiome with low diversity can increase the risk of autism, anxiety, schizophrenia, Parkinson’s disease, and Alzheimer’s disease.

Boost Your Mental Health Through Your Gut Microbiome

Making dietary choices that improve your gut health can also improve your mental health. We’ll highlight some dietary strategies below that you can use to give your health a boost.

Ketogenic Diet

While a low carbohydrate diet isn’t for everyone, it can yield protective benefits for your brain and gut. A low-carb, high-fat diet like the ketogenic diet causes your body to use fat for fuel instead of carbohydrates. This results in the production of ketone bodies.

Research shows that a ketogenic diet affects the gut microbiome differently than a high-fat diet alone. The production of ketone bodies reduces the growth of inflammatory bacteria in the gut microbiome.

Remarkably, a ketogenic diet may improve symptoms of autism, depression, epilepsy, cancer, Alzheimer’s disease, and Parkinson’s disease.

Low-FODMAP diet

A low-FODMAP diet is a diet that limits the consumption of easily fermentable carbohydrates. This diet restricts certain carbohydrates that trigger gastrointestinal symptoms and allows you to eat carbohydrates that don’t bother you.

High FODMAP foods can worsen cramping, bloating, gas, and diarrhea for people with IBS.

Research shows that a low-FODMAP diet can improve long-term quality of life, gastrointestinal symptoms, fatigue, anxiety, and depression in people with IBS.

High-FODMAP carbs to avoid on this diet include:

  • Fruits such as apples, mangos, pears, watermelon, figs, cherries, and avocados
  • Dairy products such as milk, custard, yogurt, and ice cream
  • Rye and wheat grains
  • Vegetables such as asparagus, broccoli, cabbage, onions, and garlic
  • Legumes such as beans, lentils, chickpeas, and soybeans


Prebiotics are plant-based fibers and polyphenols that feed the beneficial bacteria in your gut. They can reduce inflammation and increase the growth of bacteria that protect against disease.

Eating prebiotic fiber may improve symptoms of inflammatory bowel disease (IBD), diarrhea, colitis, and constipation. Research shows that prebiotics may also reduce the risk of colon cancer, improve fat breakdown, increase calcium absorption, and improve food allergies.

But these aren’t the only benefits of adding more prebiotics to your diet. Prebiotics may also reduce stress, anxiety, and depression and enhance cognition and learning.

Good sources of prebiotics include:

  • Asparagus
  • Onions
  • Garlic
  • Leek
  • Bananas
  • Chicory root
  • Oats
  • Wheat
  • Dark chocolate


Probiotics are foods that contain live, beneficial bacteria. Eating probiotic foods may improve your metabolism, immunity, and endocrine function. But research on probiotics is limited in humans.

When it comes to your digestive health, probiotics may promote the integrity of the gut lining. They may also improve communication between nerve cells, brain development, inflammation, and behavior. Some probiotic bacterial strains may even alleviate depression, anxiety, and autism symptoms.

Foods that contain probiotics include:

  • Yogourt
  • Kefir
  • Sauerkraut
  • Tempeh
  • Kimchi

TIP: Many of my patients ask which probiotic supplement to take. Unfortunately, many over-the-counter probiotics may not be effective. I prefer soil-based spore-forming probiotics because there is significant evidence that these are the only ones that have been shown to improve the microbiome and survive until they reach the colon.

Rethinking the Stress and IBS Relationship

Irritable bowel syndrome (IBS) is a chronic condition that affects the movement of waste through the large intestine. This condition can cause abdominal pain, abdominal distention, bloating, flatulence, diarrhea, and constipation.

Researchers and doctors thought that anxiety and depression caused IBS for many years. But it may actually be the other way around.

Inflammation in the gut sends signals to the brain that can lead to mood changes and stress. The gut-brain connection may explain why people with IBS and functional bowel problems often experience anxiety and depression.

Integrative Medicine Treatments

Because the gut and brain communicate back and forth, IBS and other digestive conditions often benefit from treatments that use both gastrointestinal and behavioral approaches.


Eating a plant-based diet can restore the balance in your gut microbiome and improve your overall health. This is because plant-based foods are rich in fiber, prebiotics, vitamins, and minerals. A healthy diet should focus on plant-based foods such as:

  • Whole grains
  • Legumes
  • Nuts and seeds

Avoiding high amounts of processed foods, fatty foods, and sugary foods can lower the risk of:

  • Inflammatory diseases
  • Obesity
  • Metabolic syndrome
  • Anxiety
  • Stress


Aerobic exercise can increase the microbiome’s diversity, which leads to improvements in your gut and brain health.

Research shows that exercise can strengthen the integrity of the intestinal lining, improve gastrointestinal symptoms, and reduce depression, anxiety, and stress in people with IBS.


Non-absorbed antibiotics are used to treat some digestive disorders. But they should only be used in the short term in specific situations like SIBO.

Stress Management

Managing your stress levels can improve your thoughts and feelings, which can turn off the body’s stress response and prevent inflammation in the gut.

Stress management strategies that you can use include:

  • Meditation
  • Yoga
  • Deep breathing
  • Journaling
  • Talk therapy

Achieving a More Balanced Gut

The gut-brain connection has an incredible impact on human health and is shifting the global treatment of digestive and brain disorders. While the exact mechanism of this connection remains unknown, gastroenterologists will continue to evaluate symptoms and treatment options that affect our two brains.

Making dietary and lifestyle choices that improve your gut health can have ripple effects on your mental health. Your diet has the most direct impact on your gut microbiome. Eating prebiotics and polyphenols can help balance and diversify your microbiome.

Everyone has a different microbiome composition, so you may need individualized treatments to manage your symptoms. But taking an integrative approach that addresses both your digestive and mental health can help you feel better overall. Talking with your doctor can help you find the best treatment plan for your condition.

Are you concerned about your gut health? If you’re looking for a board-certified gastroenterologist in Plano, TX, call our office at (972) 867-0019 or click to request an appointment.